Back when Brandy was a teenager, she was already sittin’ on top of the world. On the latest episode of MTV’s “When I Was 17,” the R&B star reminisced about balancing schoolwork while filming her hit show “Moesha,” her shopping habit, bum rushing the stage after winning a Grammy for “The Boy Is Mine,” and how she fainted when Rodney “Darkchild” Jerkins introduced her and her brother Ray J to the King of Pop.